1. Field of the Invention
The present invention relates to a mountable microstructure used when mounting an element on a base substance (substrate), and is suitable for example for an optical interconnection device between laminated IC chips as with for example a one-chip computer.
2. Description of the Related Art
In order to achieve even higher speed for a computer, a one-chip computer is considered where IC chips, such as a CPU and DRAM, is laminated, and the exchange of data between chips is performed with optical signals. Regarding an optical interconnection device for such a one-chip computer, if for example respective IC chips are laminated so that the light emitting element of a certain IC chip faces a light receiving element of another IC chip, the emission light of one light emitting element can be directly received by the other IC chip. Consequently, if data is carried in the light, then data transmission between IC chips can be performed at high speed. Furthermore, if the IC chip provided with the light receiving element is further laminated, the signal of one light emitting element can be received by a plurality of light receiving elements, that is the data of one IC chip can be transmitted simultaneously to a plurality of other IC chips. Therefore an extremely high speed optical bus can be formed. For the light emitting element of such an optical interconnection device between laminated IC chips, a vertical resonator type surface emitting laser element for which the aperture of the discharge port is small is ideal.
On the other hand, there is an element mounting technique disclosed for example in U.S. Pat. No. 5,904,545. This element mounting technique, as shown in FIG. 10 involves for example forming concavities A of a predetermined shape on an upper surface of a base substance C of for example a substrate or a film or the like, molding microstructures B of a shape for engaging in these concavities, mixing the microstructures B in a predetermined fluid to make a slurry, and then flowing this slurry along the upper surface of the base substance C so that elements comprising the microstructures B of the same shape as the concavities A are engaged under gravity in the concavities A, to thereby mount these. In this conventional technology also there is disclosure of forming for example a surface emitting laser element comprising GaAs, into a microstructure of a shape for engaging in the concavities, and mounting the surface emitting laser element by means of the aforementioned mounting technique. Here the base substance is formed from Si and the concavities on the upper surface of the base substance are formed by Si anisotropic etching.
Incidentally, as is well known, in Si anisotropic etching, the accuracy of the shape to be formed is extremely high. That is, the shape of the concavities formed on the upper surface of the base substance has an extremely good accuracy. However, with a compound semiconductor represented by the surface emitting laser element, even if anisotropic etching is effected, the accuracy of the shape is not very high. That is, for a microstructure of a compound semiconductor formed by anisotropic etching, the shape accuracy is inferior. Consequently, no matter how high the shape accuracy of the concavities on the surface of the base substance, the shape accuracy of the microstructures of the compound semiconductor is low, and hence the positioning accuracy for mounting as an element is low.
The present invention has been developed in order to solve the above problems, with the object of providing a mountable microstructure for which the element mounting location accuracy is extremely high.
In order to solve the above problems, a mountable microstructure according to a first aspect of the present invention is a mountable microstructure which is engaged and mounted in a concavity formed at a predetermined location on an upper surface of a base substance, by mixing in a fluid to form a slurry and flowing the slurry over the upper surface of the base substance, wherein there is provided an Si block of a shape for engaging in the concavity on the upper surface of the base substance, and a compound semiconductor element formed on an upper surface of the block.
Moreover, a mountable microstructure according to a second aspect of the present invention is one where in the first aspect, the Si block and the compound semiconductor element are bonded by a compound semiconductor-Si direct bonding.
Furthermore, a mountable microstructure according to a third aspect of the present invention is one where in the first aspect, the Si block and the compound semiconductor element are bonded by an InP-Si direct bonding.
Moreover, a mountable microstructure according to a fourth aspect of the present invention is one where in the first aspect, the Si block and the compound semiconductor element are bonded by a GaAsxe2x80x94Si direct bonding.
Furthermore, a mountable microstructure according to a fifth aspect of the present invention is one where in the first aspect, the Si block and the compound semiconductor element are bonded via a metal film.
Moreover, a mountable microstructure according to a sixth aspect of the present invention is one where in the first aspect, the Si block and the compound semiconductor element are bonded via solder.
Furthermore, a mountable microstructure according to a seventh aspect of the present invention is one where in the first aspect, the Si block and the compound semiconductor element are bonded via resin.
Moreover, a mountable microstructure according to an eighth aspect of the present invention is one where in the first aspect, the Si block and the compound semiconductor element are bonded via an SiO2 film.
Furthermore, a mountable microstructure according to a ninth aspect of the present invention is one where in the first aspect, the Si block and the compound semiconductor element are bonded via an SiO2 film and an AlGaAs layer.
Moreover, a mountable microstructure according to a tenth aspect of the present invention is one where in any one of the first through ninth aspects, a plurality of the compound semiconductor elements are formed on each Si block.
Furthermore, a mountable microstructure according to an eleventh aspect of the present invention is one where in any one of the first through tenth aspects, individual elements are formed on the Si block itself.
Moreover, a mountable microstructure according to a twelfth aspect of the present invention is one where in the eleventh aspect, the individual elements formed on the Si block itself and the compound semiconductor element are arranged so as to overlap or face each other.
Furthermore, a mountable microstructure according to a thirteenth aspect of the present invention is one where in the eleventh aspect, the individual elements formed on the Si block itself and the compound semiconductor element are arranged so as to be displaced from each other.
Moreover, a mountable microstructure according to a fourteenth aspect of the present invention is one where in any one of the first through thirteenth aspects, all of the electrodes for the compound semiconductor element are formed on the upper surface of the Si block.
Furthermore, a mountable microstructure according to a fifteenth aspect of the present invention is one where in any one of the first through thirteenth aspects, any one of the electrodes for the compound semiconductor element is made common with the electrodes for the Si block.
Moreover, a mountable microstructure according to a sixteenth aspect of the present invention is one where in the fifteenth aspect, a high resistance layer with a resistance greater than 1xc3x97104 xcexa9 is provided between the compound semiconductor element electrode formed on the upper surface of the Si block and the Si block.
Furthermore, a mountable microstructure according to a seventeenth aspect of the present invention is one where in the sixteenth aspect, the high resistance layer comprises a compound semiconductor.
Moreover, a mountable microstructure according to an eighteenth aspect of the present invention is one where in the sixteenth aspect, the high resistance layer comprises a compound semiconductor doped with Cr and O.
Furthermore, a mountable microstructure according to a nineteenth aspect of the present invention is one where in the sixteenth aspect, the high resistance layer comprises an oxide.
Moreover, a mountable microstructure according to a twentieth aspect of the present invention is one where in the sixteenth aspect, the high resistance layer comprises a nitride.
Furthermore, a mountable microstructure according to a twenty first aspect of the present invention is one where in the sixteenth aspect, the high resistance layer comprises a resin.
Moreover, a mountable microstructure according to a twenty second aspect of the present invention is one where in the fifteenth aspect, a current blocking layer using a PN connection is provided between the compound semiconductor element electrode formed on the upper surface of the Si block and the Si block.
Furthermore, a mountable microstructure according to a twenty third aspect of the present invention is one where in the twenty second aspect, the current blocking layer is formed by laminating layers of a P-type semiconductor and an N-type semiconductor in PNP or NPN order.
Moreover, a mountable microstructure according to a twenty fourth aspect of the present invention is one where in the twenty third aspect, a contact layer in the immediate vicinity of the Si block is used as the P-type semiconductor or the N-type semiconductor constituting the current blocking layer.
An optical transmission apparatus according to a twenty fifth aspect of the present invention is one where a base substance with a mountable microstructure according to any one of the first through twenty fourth aspects which includes a light emitting element mounted in a concavity, and a base substance with a mountable microstructure according to any one of the first through twenty fourth aspects which includes a light receiving element mounted in a concavity, are laminated so that the light emitting element and the light receiving element face each other.
An optical transmission apparatus of a twenty sixth aspect of the present invention is one having a light emitting section comprising a base substance with a mountable microstructure according to any one of the first through twenty fourth aspects which includes a light emitting element mounted in a concavity, and a light receiving section comprising a base substance with a mountable microstructure according to any one of the first through twenty fourth aspects which includes a light receiving element mounted in a concavity.
In the mountable microstructure according to the first aspect of the present invention, the construction is such that the compound semiconductor element is formed on the upper surface of the Si block of a shape for engaging with the concavity on the upper surface of the base substance. Therefore the shape accuracy of the Si block can be increased by anisotropic etching, and this Si block is engaged in a concavity with a high shape accuracy, so that the mounting position accuracy of the compound semiconductor element is increased.
Furthermore, in the mountable microstructure according to the second aspect of the present invention, the construction is such that the Si block and the compound semiconductor element are bonded by direct bonding. Therefore the mountable microstructure according to the first aspect can be easily implemented.
Moreover, in the mountable microstructure according to the third aspect of the present invention, the construction is such that the Si block and the compound semiconductor element are bonded by an InPxe2x80x94Si direct bonding. Therefore the mountable microstructure according to the first aspect can be easily implemented.
Furthermore, in the mountable microstructure according to the fourth aspect of the present invention, the construction is such that the Si block and the compound semiconductor element are bonded by a GaAsxe2x80x94Si direct bonding. Therefore the mountable microstructure according to the first aspect can be easily implemented.
Moreover, in the mountable microstructure according to the fifth aspect of the present invention, the construction is such that the Si block and the compound semiconductor element are bonded via a metal film. Therefore the mountable microstructure according to the first aspect can be easily implemented.
Furthermore, in the mountable microstructure according to the sixth aspect of the present invention, the construction is such that the Si block and the compound semiconductor element are bonded via solder. Therefore the mountable microstructure according to the first aspect can be easily implemented.
Moreover, in the mountable microstructure according to the seventh aspect of the present invention, the construction is such that the Si block and the compound semiconductor element are bonded via resin. Therefore the mountable microstructure according to the first aspect can be easily implemented, and the resin becomes an insulating layer between the compound semiconductor element and the Si block.
Furthermore, in the mountable microstructure according to the eighth aspect of the present invention, the construction is such that the Si block and the compound semiconductor element are bonded via an SiO2 film. Therefore the mountable microstructure according to the first aspect can be easily implemented.
Moreover, in the mountable microstructure according to the ninth aspect of the present invention, the construction is such that the Si block and the compound semiconductor element are bonded via an SiO2 film and an AlGaAs layer. Therefore the mountable microstructure according to the first aspect can be easily implemented.
Furthermore, in the mountable microstructure according to the tenth aspect of the present invention, the construction is such that a plurality of the compound semiconductor elements are formed on each Si block. Therefore even higher density mounting is possible.
Moreover, in the mountable microstructure according to the eleventh aspect of the present invention, the construction is such that individual elements are formed in the Si block itself. Therefore not only can the compound semiconductor element be simply mounted on a base substance, but a plurality of functions can be obtained with a single mountable microstructure, and even higher density mounting is possible.
Furthermore, in the mountable microstructure according to the twelfth aspect of the present invention, the construction is such that the individual elements formed on the Si block itself and the compound semiconductor element are arranged so as to overlap or face each other. Therefore for example in the case where the compound semiconductor element is a light emitting element, and the individual elements formed on the Si block itself are light receiving elements, the light emitting condition of the light emitting element can be monitored by the light receiving elements.
Moreover, in the mountable microstructure according to the thirteenth aspect of the present invention, the construction is such that the individual elements formed on the Si block itself and the compound semiconductor element are arranged so as to be displaced from each other. Therefore for example in the case where the compound semiconductor element is a light emitting element, and the individual elements formed on the Si block itself are light receiving elements, if the base substance is arranged so that two mountable microstructures face each other in opposite directions, the light emitting condition of mutual light emitting elements can be monitored by mutual light receiving elements.
Furthermore, in the mountable microstructure according to the fourteenth aspect of the present invention, the construction is such that all of the electrodes for the compound semiconductor element are formed on the upper surface of the Si block. Therefore inspection of the compound semiconductor element is facilitated. Furthermore, in the case where individual elements are formed on the Si block itself, the elements of the Si block itself and the compound semiconductor element can be easily driven individually.
Moreover, in the mountable microstructure according to the fifteenth aspect of the present invention, the construction is such that any one of the electrodes for the compound semiconductor element is made common with the electrodes for the Si block. Therefore the number of electrodes can be reduced, and simplification of construction and a lower cost can be achieved.
Furthermore, in the mountable microstructure according to the sixteenth aspect of the present invention, the construction is such that the high resistance layer with a resistance greater than 1xc3x97104 xcexa9 is provided between the compound semiconductor element electrode formed on the upper surface of the Si block and the Si block. Therefore in the case where individual elements are formed on the Si block itself, the elements of the Si block itself and the compound semiconductor element are insulated, and can be easily driven individually.
Moreover, in the mountable microstructure according to the seventh aspect of the present invention, the construction is such that the high resistance layer comprises a compound semiconductor. Therefore the mountable microstructure according to the sixteenth aspect can be easily implemented.
Furthermore, in the mountable microstructure according to the eighteenth aspect of the present invention, the construction is such that the high resistance layer comprises a compound semiconductor doped with Cr and O. Therefore the mountable microstructure according to the sixteenth aspect can be easily implemented.
Moreover, in the mountable microstructure according to the nineteenth aspect of the present invention, the construction is such that the high resistance layer comprises an oxide. Hence the high resistance layer can be easily formed by for example oxidizing the Si block. Therefore the mountable microstructure according to the sixteenth aspect can be easily implemented.
Furthermore, in the mountable microstructure according to the twentieth aspect of the present invention, the construction is such that the high resistance layer comprises a nitride. Hence the high resistance layer can be easily formed by for example nitriding the Si block. Therefore the mountable microstructure according to the sixteenth aspect can be easily implemented.
Moreover, in the mountable microstructure according to the twenty first aspect of the present invention, the construction is such that the high resistance layer comprises a resin. Therefore the mountable microstructure according to the sixteenth aspect can be easily implemented.
Furthermore, in the mountable microstructure according to the twenty second aspect of the present invention, the construction is such that the current blocking layer using a PN connection is provided between the compound semiconductor element electrode formed on the upper surface of the Si block and the Si block. Therefore, in the case where individual elements are formed on the Si block itself, the elements of the Si block itself and the compound semiconductor element are insulated, and can be easily driven individually. Moreover, the current blocking layer can be easily formed by semiconductor processing the Si block.
Moreover, in the mountable microstructure according to the twenty third aspect of the present invention, the construction is such that the current blocking layer is formed by laminating layers of a P-type semiconductor and an N-type semiconductor in PNP or NPN order. Therefore the current blocking layer can be easily formed by semiconductor processing of the Si block.
Furthermore, in the mountable microstructure according to the twenty fourth aspect of the present invention, the construction is such that the contact layer in the immediate vicinity of the Si block is used as the P-type semiconductor or the N-type semiconductor constituting the current blocking layer. Therefore the formation of the current blocking layer is further simplified, and a simplification of construction and a lower cost is possible.